1. From the Departments of Medicine (K.M.P., T.C.W., K.M.Z., K.L., D.M.H., S.C.C., E.B.S.) and Radiology (C.R.D., J.M.L., F.C.-P.), University of Pittsburgh School of Medicine, Pittsburgh, PA; Cardiovascular Magnetic Resonance Center (K.M.P., T.C.W., K.S.P., K.M.Z., D.M.H., C.R.D., J.M.L., F.C.-P., S.C.C., E.B.S.) and Heart and Vascular Institute (K.M.P., T.C.W., K.M.Z., D.M.H., C.R.D., J.M.L., F.C.-P., S.C.C., E.B.S.), UPMC, Pittsburgh, PA; National Heart, Lung, Blood Institute, Bethesda, MD (P.K.);...